Liquid fuel pumping apparatus



April 22, 1969 I I MDRoRl 3,439, 21

LIQUID FUEL PUMFING APPARATUS Filed April 14. 1967 Sheet of s -I I I6April 22, 1969' M, DROR. 3,439,621

LIQUID FUEL PUMPING APPARATUS Filed April 14, 1967 She'et" of :s

pril 22, 1969 M. DRORI 3,439,621

LIQUID FUEL PUMPING APPARATUS Filed April 14, 1967 a Sheet 3 013 UnitedStates Patent US. Cl. 103-2 Claims ABSTRACT OF THE DISCLOSURE A liquidfuel p'umping apparatus for supplying fuel to internal combustionengines having an injection pump and a passage through which theinjection pump is placed in communication with one end of a cylinderduring the filling stroke, the cylinder containing a shuttle which ismoved into contact with an abutment, a one way valve being provided insaid passage, the valve permitting the zflow of fuel to the injectionpump and being positioned to trap cavities formed in the fuel when theshuttle strikes the abutment, so that said cavities are not collapsedsuddenly when the injection pump delivers fuel.

This invention relates to liquid fuel pumping apparatus for supplyingfuel to an internal combustion engine and of the kind comprising incombustion, an injection pump which is arranged to be driven in timedrelationship with the engine, and a shuttle movable within a cylinder,one end of said cylinder serving to store a quantity of fuel whichduring a filling stroke of the injection pump is displaced to theinjection pump by moving the shuttle towards said one end of thecylinder, and an abutment for limiting the movement of the shuttletowards said one end of the cylinder.

With such apparatus it has been found that when the shuttle strikes theabutment a cavity is for-med in the passage which connects said one endof the cylinder and the injection pump. Following a filling stroke ofthe injection pump this passage is closed at a point adjacent said oneend of the cylinder with the result that at the start of the injectionstroke the cavity is rapidly closed thereby resulting in erosion of thepassage at the position of the cavity.

The object of the present invention is to provide such an apparatus in asimple and convenient form in which the risk of erosion as describedtaking place is minimised.

In the accompanying drawings:

FIGURE 1 is a sectional side view of one example of a pumping apparatusto which the invention can be applied and showing the apparatus duringthe injection stroke the section being taken on the line 11 of FIGURE 3,

FIGURE 2 is a sectional side view of the apparatus in the same positiontaken on the line 2-2 of FIGURE 3,

FIGURE 3 is a section on the line 33 of FIGURE 1,

FIGURE 4 is a section on the line 4-4 of FIGURE 1,

FIGURE 5 is a section on the line 55 of FIGURE 1,

FIGURE 6 is a section on the line 6-6 of FIGURE 1, and

FIGURE 7 is a fragmentary section to an enlarged scale of part of theapparatus shown in FIGURE 1 in accordance with the present invention.

Referring to the drawings there is provided a body part 10 in which ismounted a rotary cylindrical distributor 11 which is adapted to bedriven in timed relationship with the engine with which the apparatus isassociated. At one end of the distributor is provided a transverselydisposed bore in which is mounted a pair of reciprocable pumpingplungers 12 which are arranged to be moved inwardly as the distributorrotates, by a plurality of cam lobes which 3,439,621 Patented Apr. 22,1969 are formed on the internal periphery of an annular cam ring 13which surrounds the distributor 11 at this point. The transverse boredefines between the pumping plungers, a pumping chamber which is incommunication with one end of a longitudinal passage 14 formed in thedistributor. The other end of this passage is in communication with aradially disposed delivery passage 15 which is adapted to register inturn and as the distributor rotates, with a plurality of outlet ports 16formed in the body part. The outlet ports are connected respectively toinjection nozzles (not shown) associated with the combustion spaces ofthe engine and the registration of the delivery passage 15 with one ofthe outlet ports 16 is arranged to occur whilst the plungers 12 arebeing moved inwardly by the cam lobes. In this manner fuel contained'within the pumping chamber is displaced to a combustion space of theengine.

At the other end of the distributor is mounted the rotary part 17 of afeed pump which has an inlet 18 and an outlet in the body part, theoutlet being connected to a supply conduit 19 disposed within the bodypart. The inlet of the feed pump in use, is connected to a source offuel so that as the distributor rotates, fuel will be supplied underpressure to the supply conduit 19. The inlet and outlet of the feed pumpare interconnected by a convenient relief valve located within a housingsecured to the body part 10 whereby the pressure of fuel delivered bythe feed pump is controlled.

At another point the longitudinal passage is in communication with aplurality of radially disposed inlet passages 20 which break out on theperiphery of the distributor and which are adapted to register in turnand as the distributor rotates, with an inlet port 21 formed in the bodypart. The communication of an inlet passage 20 with the inlet port 21 isarranged to occur whilst the delivery passage 15 is out of register witha delivery port 16 and also during the time when the plungers 12 arepermitted to move outwardly by the cam lobes. The inlet port 21 isformed at one end of a cylinder 22 which is defined in the body part andwhich contains a reciproachable shuttle 23. The movement of the shuttletowards said one end of the cylinder is limited by its abutment with theend of the cylinder and the movement of the shuttle in the oppositedirection is limited by a stop 24 which conveniently is adjustable fromthe exterior of the apparatus. Formed on the periphery of thedistributor and in a position to register in turn with the inlet port isa first series of longitudinal groove 25. The grooves are disposedintermediate the inlet passage 20 and are in communication at one endwith a first circumferential groove 26 formed in the periphery of thedistributor. This groove is in communication with the supply conduit 19by way of an adjustable throttle 27 the setting of which can becontrolled manually or by means of a governor and the arrangement issuch that when one of the first series of grooves 25 registers with theinlet port 21, fuel will flow to said one end of the cylinder therebycausing the shuttle to be moved away from the inlet port. During thismovement fuel is expelled from the other end of the cylinder to aconvenient drain. For this purpose the other end of the cylinder is incommunication with a second circumferential groove 28 formed in theperiphery of the distributor and from which extends a secondlongitudinal groove 29. This groove is arranged to register in turn asthe distributor rotates with a plurality of spill ports 30 therebyallowing fuel to escape from the other end of the cylinder. In analternative arrangement a plurality of grooves 29 are provided and asingle spill port 30.

When the inlet port 21 registers with one of the inlet passages 20 fuelunder pressure is adimtted to the other end of the cylinder to move theshuttle towards said one end thereof and into contact with an abutment,thereby to displace the fuel contained in said one end of the cylinder22 to the longitudinal passage 14 and the pumping chamber. For thispurpose the second groove is arranged to register in turn with aplurality of supply ports 31, formed in the body part and incommunication with the supply conduit 19.

In use, fuel which is contained within the pumping chamber is deliveredto a combustion space of the engine during an injection stroke of theapparatus and whilst this is occurring fuel for subsequent delivery isbeing metered to said one end of the cylinder. The maximum quantity offuel which can be delivered by the apparatus is determined by themovement of the shuttle 23 and this quantity can be adjusted by varyingthe setting of the stop 24.

Whilst such pumps function very satisfactorily in use, it has been foundthat when the shuttle strikes an abutment at said one end of thecylinder cavitation of the fuel within the connected inlet passage 20may occur. During the next injection stroke of the apparatus the cavityor cavities are violently collapsed by the action of the increased fuelpressure within the inlet passage. Unfortunately, the clearing of thecavity or cavities in this manner causes erosion of the passage with theresult that the life of the apparatus is reduced. It has been found thatthe cavity or cavities form at or near the outer ends in the inletpassages 20 and in order to overcome the problem one way vales 35 (shownfor clarity only in FIGURE 7) are provided in each of the inlet passages20 adjacent their inner ends. These valves are disposed so as to permitfuel to flow from the inlet port to the longitual passage but to preventflow of fuel in the opposite direction. For convenience and in order toincrease the volume in which the cavity or cavities can form the outerends of the inlet passages are in communication with an annular groove36 formed on the periphery of the distributor and from which extend aplurality of equi-angularly spaced grooves 37 which are arranged toregister in turn with the inlet port 21. These in fact constitute partsof the inlet passages and if desired only one of the inlet passages aspreviously described need be provided. If this is the case then only oneone-way valve is provided usually however two such passages and valveswill be provided in order to maintain balance.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. In a liquid fuel pumping apparatus for supplying fuel to an internalcombustion engine comprising in combination an injection pump adapted tobe driven in timed relationship with the engine and having a rotatabledistributor member; a body housing said pump and member; a passagethrough said member by which said injection pump is placed incommunication with one end of a metering cylinder during the fillingstroke of said pump to receive a predetermined amount of fuel; furtherpassages adapted to carry said fuel from said injection pump -toinjection nozzles; an inlet metering shuttle movable within saidcylinder, said one end of said cylinder adapted to store saidpre-determined amount of fuel which is displaced to said injection pumpduring its filling stroke by moving said shuttle towards said one end ofsaid cylinder; an abutment located at said one end of said cylinder forlimiting the movement of said shuttle; and a one-way valve positionedbetween said abutment and said injection pump in said passagecommunicating with said injection pump to allow fuel to flow to saidinjection pump but being so placed that any cavities formed in saidpassage as a result of said shuttle striking said abutment will belocated between said one-way valve and said abutment.

2. An apparatus as claimed in claim 1 further comprising a port formedin said body and in communication with said one end of said cylinder,during the filling of said injection pump said port registers with saidpassage in said member.

3. An apparatus as claimed in claim 2 wherein said passage includes atleast one radially disposed portion in which said valve is mounted.

4. An apparatus as claimed in claim 3 wherein said distributor member isprovided with a circumferential groove on its periphery having a lateralgroove in communication therewith for registration with said port, saidgrooves forming part of said passage and acting as in increased volumein which said cavities can form.

5. An apparatus as claimed in claim 4 wherein two radially disposedportions are provided, each having a one-way valve and eachcommunicating with said grooves.

References Cited UNITED STATES PATENTS 3,025,797 3/19'62 Hutcheon.

3,035,523 5/1962 Kemp et al.

3,079,862 3/1963 Raibaud.

3,101,079 8/1963 Evans 123--139 X 3,204,561 9/ 1965 Roosa 10=323,292,546 12/ 1966 Evans.

3,356,031 12/19'67 Glikin 1032 DONLEY I. STOCKING, Primary Examiner.

WARREN J. KRAUSS, Assistant Examiner.

